Conventional technologies for manufacturing trench semiconductor power devices are continuously challenged to further reduce the manufacturing cost by shrinking the size of a device die. Since 0.18 um technologies having trenched contacts filled with tungsten (W) contact metal plugs have been applied to semiconductor power devices, the active area of a trench semiconductor power device has been shrunk at least two times for low voltage products (<100 V). However, the size of a gate metal pad area is still kept the same as before for gate wire bonding (e.g., for 2 mil Au or Cu wire requires about 160 um×160 um gate metal pad while for 5 mil Al wire requires about 500 um×400 um gate metal pad). Therefore, the gate metal pad area becomes more pronounced (>10%) comparing to the active area of small devices, especially for the devices having gate metal pad bonded with Al wire. Please refer to FIG. 1 for a prior art showing a top view of a conventional trench MOSFET (Metal Oxide Semiconductor Field Effect Transistor) device where the dash-dotted line illustrates a source metal pad 101 and the dot pattern illustrates a gate metal pad 100. In FIG. 1, a plurality of closed active cells comprising multiple W contact metal plugs are only located underneath the source metal pad 101, and the gate metal pad 100 is only used for gate wire bonding by being connected to poly-silicon filled in gate trenches (as illustrated in FIG. 1) under the source metal pad 101 through at least one gate contact trench (as illustrated in FIG. 1) filled with the poly-silicon. Consequently, the gate metal pad 100 could become more pronounced comparing to the source metal pad area 101 as the device die shrinking, which could hamper cost reduction.
Therefore, there is still a need in the art of trench semiconductor power device, to provide a novel cell structure, device configuration and manufacturing process that would shrink the device die for cost reduction without sacrificing other performances and improve other characteristics of the trench semiconductor power device.